In older versions of RM (i.e. RM7), you could highlight a person in the main index, then click on Web Search. From there you could select a provider and search for the person. I used to have 10 or 12 saved websites to choose from.
The custom providers are held in file RootsMagicUser.xml in folder C:\Users{yourusername}\AppData\Roaming\RootsMagic\Version 10 (or which version you use) so get lost when you upgrade.
I’ve got around 20 custom providers because being in the UK I don’t use the provided US sites and you can tailor the URL to be specific to record sets or locations e.g. 1921 census or Devon Parish records.
I recommend keeping a note of the providers you set up and the URL you used so that you can re-create them.